Slide rail support for inductor furnace workpieces



Jan. 4, 1949. H. A. STRICKLAND, JR 2,457,846

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INVENTOR Harold 7@ Stcklandjr.

ATTORNEY Patented Jan. 4, 1949 SLIDE RAIL SUPPORT FOR IDUCTOR FURNACEWORKPIECES Harold A. Strickland, Jr., Detroit, Mich., assignor, by mesneassignments, to The Ohio Crankshaft Company, Cleveland, Ohio, acorporation of Ohio Application April 11, 1946, Serial No. 661,234

6 Claims. 1 This invention relates to furnace construction, withparticular reference to structure for sup,- porting the charge in thefurnace chamber.

In induction heating furnaces primarily a tu- -bular heat chamber isprovided lined with iirev brick or the like in which, as shown in mycopending application Serial No. 384,503 for Electric furnace machine,now Patent No. 2,408,350, a group of axially aligned tubes is embeddedin the rebrick but projecting above the inner surface of the iirebrickto afford an all-metal grille support for the workpiece. These tubes arelaterally displaced along the surface of the rebrick wall. Heretoforethe front or inlet extension of these tubes connecting to a. source ofcoolant projected radially from the furnace mouth. These projectingsections afforded no meansof support in themselves and hence it becamenecessary to weld or otherwise secure to the tubing at the inlet endsupporting rods which were bolted to the coil supporting structure.

A primary object of this invention is to provide a. support tube shapeat the mouth end of the furnace which lends itselfl to easy support ofthe tubes without requirement for additional fastening means.

Another object of the invention is to provide a support tube structurewhich will lpermit easy assembly of the support grille withinthe furnacecoil and into engagement with the external supporting means of the tube.

Still another object is to provide a support tube structure which allowsconstruction of sealing cylinders at the front end of the furnacewithout important modification of the cylinder.

I attain the above-mentioned objects by the construction hereinafterdescribed and shown in the accompanying gure of the drawing, wherein thevapor-sealing construction is shown in a 'longitudinal sectionalelevation of the furnace unit.

The furnace of the invention as shown is in general similar to thatshown in 'my copending application above referred to. The furnace is inthe type of an induction coil unit, generally indicated by the numeralI. The coil 2 is formed of a number of turns of hollow square conductorappropriately insulated from each other by mica or mica-containingstrips and on the inner and outer sides also by mica or mica-containingtubing which is appropriately heat-resistant as well as electricallynon-conducting. As shown, there are two layers of tubing interior of thecoil, as indicated by the numeral 3. A tube 4 formed ofasbestos-containing material, such as Transite, is blocked onto the coilsurface to serve as protection therefor, there #being an additionalouter tubing of mica insulation intermediate the protective layer andthe coil tube. Interior of the inner mica tube insulation is a layer ofiirebrick in which is embedded axially extending and circumferentiallydisplaced load-bearing rods or rails 5. These rails are hollow for thepassage of coolant and bear on their inner surfaces projecting lugs 6 ofrelatively hard metal which take the friction and wear of the workpiecein its movement in and out of the furnace chamber. These rails also bearbutterfly plates l which extend over the rebrick edges to retain thesame in place. At the rear end of the furnace chamber a push-out rod 8for forcing out the workpiece after the heating thereof is shown. Aholding tube 9 fastened to the casing wall Ill forms a support for thepush-out rod.

The furnace coil and associated layers of insulation and rebrick areheld in place and supported by end plates I I and I2 to which the unitis xed by means of support rods i3. These rods carry end coil springs I4so that the pressure of the rod acting as a bolt is yieldable betweenthe plates II and I2 thus holding the unit yieldably in position. Theseplates are preferably formed of asbestos-containing material, such asTransite.

Intermediate the rear support plate II of the coil unit and the casingI0 is placed a cylindrical drum I5 of insulation material. This drummakes close contact at either end adjacent the adjacent plate and casingsurfacesso as to be substantially vapor and gas-proof.

At the front end of the furnace there is positioned a mouthpiece 20having inwardly and annularly projecting fingers 2|, the ends of whichbeing in alignment with the inlet opening of the furnace chamber. Thismouthpiece serves as a guide to workpieces being inserted within thefurnace. The mouthpiece is supported on the front casing wall 22, asshown. Intermediate the casing 22 and the front Transite plate I2 asecond cylindrical insulation drum 23 is provided, similar in placementto the drum I5 at the rear furnace end. This drum 23 also makes closecontact with the plate I2 and casing 22 to provide at the front of thefurnace a substantially vapor and gas-proof enclosure.

In the disclosure of my copending application hereinabove referred tothe projecting ends of the rails at the front end of the furnace are ex'tended outwardly radially to the point of connection with the coolantsource or to the flexible couplings employed. This construction requiresthe welding of holding rods to the rails at the front end for attachmentto the front plate support. In the present arrangement I have found itdesirable to reverse the front ends of the rails so that they extend fora short distance parallel to the main rail section in a reverse section24. This reverse section of each rail is passed through registeringopenings in the front plate I2, which openings are parallel to the axisof the coil and the main section of the rails. Accordingly, it isapparent that these rails may be slid outwardly for removal or inwardlyfor assembly as desired and that such rail movement does not disturb`the fixed seal of the drum 23. It is noted that ithis parti-cular hookcurvature of the front end `of the rails with insertion of the aperturesthrough the plate I2 serves as support means for the front end of therails making the addition of auxiliary holding means unnecessary. Therear en'd ofthe rails is supported by I-bars 25 on the rear supportyplate lil, as shown.

As exemplifying the electrical conductor system of the furnace there isshown the supply'bus `bars 26 and 2l spaced by insulation 28 at thebase-of the furnace. Appropriate taps to the coil rare made through busliars 29 and the end con `cluctors 3B which also supply coolant for thecoil. The close placement of the bus bars -26 and 21 is desirable toreduce reactance in the electrical circuit, but such placement brings upthe problem vof leakage as induced by penetration of oil vapor from thefurnace chamber. The arrangeiment as described hereinabove'andillustrated in `thedrawing effectively obviates leakage and consequentlyefficiency drop arising from oil vapor penetration.

The showing of the drawing is primarily for illustration of the properof the vinvention. Obviously modifications may be made inthe generalarrangement and details of the disclosure ycoming within the scope ofthe appended claims.

What is claimed is:

l. In furnace construction includinga tubular induction heating coil,heateresistant tubing -fnr'mingan-inner lining for saiducoil,heati'esist "aritceramic tubing within said lining and :form- Iing aiheat chamber, workpiece-suppo1-ting tubes said extensions beingreversely turned to form 4reverse end sections external to the grille,and

end support plates for the coil, the front end plate having directconnection to the reverse end sections of the support tubes.

3. In furnace construction, a tubular refractory lining for the furnacechamber, a plurality of axiallyaligned and `radially displaced supporttubes partially embedded in the inner surface of said lining, said tubeshaving a front furnace end extension having sections outwardly turnedrelative to the lining tube axis and terminal sections parallel to thelining tube axis, and end supports 4for said lining and tubes, theterminal front .extensionof `the support tubes being adapt- Jed to seatin apertures formed in the front sup i `port for .holding Ithe tubes andlining in fixed position.

j. In furnace construction having a tubular furnace chamber, a supporttube adapted for insertion in said furnace chamber for support of aworkpiece to be heated, said tube consisting of an extended sectionnormally positioned within the `furnace chamber and a front end sectionextended Ioutside the chamber, said front end section including areversely turned terminal parallel to the mainstraight section of thetube. anda joining connection between the straight section-and saidterminal.

5. In `furnace construction having ya tubular .furnace chamber, a'support tube adapted for insertion in `said furnace chamber for supportof a workpiece ,to be heated, said tube consisting of lan extendedYsection normally positioned within the furnacechamber'and a front endsection positioned outside the chamber, said front end section includinga reversely turned terminal and a -joining section between the extendedsection and said terminal.

6. In furnace construction, a tubular refractory lining lfor the furnacechamber, a plurality of axiallyaligned and -radiallydisplaced supporttubes secured to the inner surfaceof said lining, said tubes having afront `furnace end extension beyond said lining having `sectionsoutwardly turned relative to the lining tube axis and reversely turnedterminal sections parallel to the lining tube axis, and end supports forsaid lining and tubes, vthe terminal sections of the support tubes beingadapted for direct connection to the front support for holding the tubesand lining iniixed position.

HAROLD A. STRICKLAND, Jn.

REFERENCES `CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,689,369 Tama Oct. 30, 19281,691,349 Harrington et al. Nov. 13, 1928 2,365,021 Strickland Dec. 12,1944 2,373,719 Strickland Apr. 1'7, 1945

